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SSC Sample Paper SSC CHSL (10+2) Sample Test Paper-10

  • question_answer
    If the radius of a sphere is increased by 2 cm. its surface area increased by 352 cm2. The radius of sphere before change is : \[\left( use\,\,\pi =\frac{22}{7} \right)\]

    A) 3 cm                            

    B) 4 cm

    C) 5 cm                            

    D) 6 cm

    Correct Answer: D

    Solution :

    Let the radius of first sphere = r cm and the radius of second sphere = (r + 2) cm \[\therefore \] Difference between surface area \[\Rightarrow \text{ }4\pi \left\{ {{\left( r+2 \right)}^{2}}-{{r}^{2}} \right\}=352\] or, \[4\times \frac{22}{7}\left\{ (r+2-r)+(r+2+r) \right\}=352\] \[\therefore \,\,\,2\times 2(r+1)=\frac{352\times 7}{4\times 22}\] \[\therefore \,\,\,r+1=\frac{352\times 7}{4\times 4\times 22}\] \[\therefore \,\,r+1=7\] \[\therefore \,\,r=7-1=6\] cm


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